1. Field of the Invention
This disclosure relates to a cranial bone surrogate and to methods of manufacture thereof. In particular, this disclosure relates to a cranial bone surrogate for high speed impact simulations and to methods of manufacture thereof.
2. Description of the Related Art
The cranial bone plays an important role in protecting the brain from damage during accidents. Bone generally comprises a multilayered structure having a high stiffness compact bone and a much lower stiffness, low density, porous structure called a trabecular bone. Cranial bone, in particular, comprises a three layer structure. The inner and outer layers are called the “tables” and consist of compact bone, which has a high density and stiffness. There is a layer between the inner and outer tables, which has a much lower density, but acts as an energy absorber and it is termed the “diploe”. In order to measure behavior of the cranial bone when subjected to a variety of impacts at different velocities, it is desirable to produce artificial materials (hereinafter termed a “surrogate material”) that can replicate bone behavior.
It has been suggested that a conventional surrogate bone material for a femur or vertebrae might include an E-fiber-epoxy composite. However, it is not known how to manufacture such a composite. Moreover, detailed structure and/or dimensions of any such composite are not known. In addition, the femur and vertebrae have different structures from the cranial bone and are never subjected to the same magnitude of forces during an impact test.
Accordingly, there is a long-felt need to develop a surrogate material that behaves similar to bone. The surrogate material can be tested in human surrogate models in a variety of simulated impact environments. By using a surrogate material that replicates the behavior and performance of a real cranial bone in high and low speed impact tests, various measurements can be made during these tests by positioning transducers at various points on the cranial bone. These measurements cannot be made with real or live specimens. In addition, the use of a surrogate material for manufacturing the cranial bone permits the measurement and characterization of the types of fractures that a live person would undergo when subjected to similar forms of impact.
It is therefore desirable to have a surrogate material that replicates the behavior of the cranial bone and that can be mass produced to perform a variety of tests under different circumstances.